/*
 * @(#)RandomUtil.java	1.0 Apr 26, 2008
 *
 *	The MIT License
 *
 *	Copyright (c) 2008 Malachi de AElfweald <malachid@gmail.com>
 *
 *	Permission is hereby granted, free of charge, to any person obtaining a copy
 *	of this software and associated documentation files (the "Software"), to deal
 *	in the Software without restriction, including without limitation the rights
 *	to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 *	copies of the Software, and to permit persons to whom the Software is
 *	furnished to do so, subject to the following conditions:
 *
 *	The above copyright notice and this permission notice shall be included in
 *	all copies or substantial portions of the Software.
 *
 *	THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 *	IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 *	FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 *	AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 *	LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 *	OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 *	THE SOFTWARE.
 */
package org.eoti.math;

import java.util.concurrent.locks.*;
import java.util.*;

public class RandomUtil
{
	protected static ReentrantLock singletonLock = new ReentrantLock();
	protected static RandomUtil singleton;
	public static RandomUtil getInstance()
	{
		// If singleton != null, then just return it (don't lock READ)
		if(singleton == null)
		{
			// don't let more that one person create the singleton
			singletonLock.lock();

			// if we were waiting for a lock, then someone else already made it
			if(singleton == null)
				singleton = new RandomUtil();

			singletonLock.unlock();
		}

		return singleton;
	}
	protected RandomUtil()
	{
		random = new Random( (new Date()).getTime() );
	}

	protected Random random;

	public static int randInt(int maxNumExclusive)
	{
		return getInstance().random.nextInt(maxNumExclusive);
	}
}
